The HiQSDR Medium Power PA with an output PEP of 8-10 Watts PEP can be directly plugged into the

HiQSDR Preselector Board. The HiQSDR MPPA is universally designed and can be used as separate driver
for bigger Amplifiers as well as QRP PA.

The Board is so designed, that all signal traces are on TOP of the PCB. The Bottom of PCB is completely
grounded and can be mounted directly to a heatsink or a Heatspreader to dissipate the exess heat.

The HiQSDR MPPA is very flexible. The high gain of the dual staged push-pull amplifier design has a gainof 40dB and allows input signals as low as 0dB to produce up to 10 Watts PEP.
The IP3 of the Amplifier is excellent: at 7.1MHz is the IP3 around -41dBc (!).
The MPPA is a broadband, highly linear amplifer and allows operation from 1 MHz up to 62 MHz.
The input ad output impedance ist 50 Ohm. The MPPA is save against shorts and open output for alimited time, but pay attention for a good cooling!
The power supply is 12..13.8 Volt DC, max. 2.5 Amps. In both push-pull stages, modern RF field-effect transitors from Hitachi are used, in the driver stage 2 x RD01MUS2 and for the second stage 2x RD07MVS1 types.

The MPPA is optimized by DL2EWN, thank you for your work, time and effort!

To transport the excess heat from the MPPA, the PCB is made from a 1mm FR4 material. Below and around the power transistors, plated thru-holes are made to transport the heat from the top of he PCB to the bottom part. Th PCB is screwed to a Heatspreader and the Power FET's RD07MVS1 are pressed to the PCB and the Heatspreader by a massive aluminium bar. Between the Heatspreader and the PCB must a heat transport material used. You can use heat transfer grease or (much better) heat transfer foils. Best heat transfer foil for this application is a pure graphite foil of 0.2mm thickness. This foil is soft and transports the heat very effective. Care must be taken because graphite is conductive, but the bottom side of the MPPA is at ground level so this is not important.
Please keep in mind that the Heatspreader is not a Heatsink! Screw the Heat connection bar at the lower side to a heatsink or a large mounting plate to allow cooling. Please keep also in mind, that you have to dissipate around 10 to 12 Watts of heat, especially if you use CW modes like RTTY, FM, PSK or WSJT.

The MPPA PCB with cooling parts (HeatSpreader/Clamp: here a prototype is shown)
MPPA from Backside: Heatspreader, without Heat-Plug